First off, welcome to the forums. I appreciate your input on the matter, however I would like to inform you that we are on a pretty good track of what the problem is and where it lies. I don't want this to throw anyone for a loop, but the main issue pointed out in this thread so far is that one day the computer worked great, all of a sudden the mobo showed little to no sign of life.
This would indicate that it is not a problem such as you described unless someone were playing around with that port, aka modding/soldering/putting the wrong plug into it.